(Trigeminal nerve) & Innervation of teeth by DR.Mahmoud Ashraf

1. Trigeminal Nerve &

3.  The fifth (V) cranial nerve &the largest of the
twelve cranial nerves.
 Provide among other functions sensory
innervation from teeth, bone, and soft tissues
of the oral cavity.
 It is composed of a small motor root and a
considerably larger (tripartite) sensory root.

4.  The three major branches of the trigeminal nerve
1. The ophthalmic nerve (V1) –Sensory-
2. The maxillary nerve (V2) -Sensory-
3. The mandibular nerve (V3) –Mixed-

5.  The 3 branches of the sensory root supply :
 the skin of the entire face.
 the mucous membrane of the cranial viscera.
 the mucous membrane of the oral cavity and
teeth, except for the pharynx and base of the
tongue.

6.  Motor fibers of the trigeminal nerve supply the
following muscles:
- Masticatory.
• Masseter
• Temporalis
• Pterygoideus medialis
• Pterygoideus lateralis
-Mylohyoid.
-Anterior belly of the digastric.
-Tensor tympani.
-Tensor veli palatini.

10.  It is purely sensory and is the smallest of the
three divisions.
 The ophthalmic division (V1) travels
anteriorly in the lateral wall of the cavernous
sinus to the medial part of the superior orbital
fissure, through which it exits the skull into
the orbit.
 branches: nasociliary, frontal, and lacrimal
nerves.

11.  It supplies :-
1. The eyeball
2. Conjunctiva
3. Lacrimal gland
4. Parts of the mucous membrane of the nose and
paranasal sinuses.
5. The skin of the forehead upper eyelids, and
nose.
 Note:When the ophthalmic nerve (V1) is paralyzed, the
ocular conjunctiva becomes insensitive to touch.

13.  Intermediate in size between ophthalmic and
mandibular divisions.
 it is purely sensory in function.
 The maxillary division (V2) travels anteriorly
and downward to exit the cranium through
the foramen rotundum into the upper
portion of the pterygopalatine fossa.

14.  As it crosses the pterygopalatine fossa, it gives
off branches to the sphenopalatine ganglion,
the posterior superior alveolar nerve, and the
zygomatic branches.
 It then angles laterally in a groove on the
posterior surface of the maxilla, entering the
orbit through the inferior orbital fissure.
 Within the orbit, it occupies the infraorbital
groove and becomes the infraorbital nerve,
which courses anteriorly into the infraorbital
canal.

17.  The maxillary division gives off branches in
four regions:
1. within the cranium -> “middle meningeal nerve”.
2. in the pterygopalatine fossa.
3. in the infraorbital canal.
4. on the face.

18. 1-The orbital branches supply the periosteum of
the orbit.
2-The nasal branches - the nasopalatine nerve,
which passes across the roof of the nasal cavity
downward and forward, It enters incisive canal,
through which it passes into oral cavity via the
incisive foramen.
-provide sensation to the palatal mucosa in the
region of the premaxilla (canines through central
incisors)

21. 3-The palatine branches :-
A-The greater (or anterior) palatine nerve.
 emerging on the hard palate through the greater
palatine foramen (which is usually located about 1
cm toward the palatal midline, just distal to the
second molar).
 Or may be located 3 to 4 mm in front of the
posterior border of the hard palate.
 supplying sensory innervation to the palatal soft
tissues and bone as far anterior as the first premolar,
where it communicates with terminal fibers of the
nasopalatine nerve

22. 3-The palatine branches :-
B-The lesser (middle and posterior) palatine
nerves.
 provides sensory innervation the soft palate.

23. 1.Posterior
superior alveolar
branches.
2. infraorbital nerve.
3. Maxillary nerve.
4. foramen rotundum.
5. greater palatine
nerve.
6.nasopalatine nerve.

24. 4-The pharyngeal branch
 leaves the posterior part of the pterygopalatine
ganglion, passes through the pharyngeal canal,
and is distributed to the mucous membrane of
the nasal part of the pharynx.

26. 1-The pterygopalatine nerves
(Ganglionic branches)
 Are two short trunks that unite in the
pterygopalatine ganglion serve as a
communication between the pterygopalatine
ganglion and the maxillary nerve.
 Postganglionic secretomotor fibers from the
pterygopalatine ganglion pass through these
nerves and back alongV2 to the zygomatic
nerve, through which they are routed to the
lacrimal nerve and the lacrimal gland.

27. 2-The Zygomatic branch :-
 Travels anteriorly, entering the orbit through the
inferior orbital fissure, where it divides into two
nerves.
1. the zygomaticotemporal supplying sensory
innervation to the skin on the side of the forehead.
2. the zygomaticofacial supplying the skin on the
prominence of the cheek
 Note: the zygomatic nerve sends a branch that
communicates with the lacrimal nerve of the
ophthalmic division.This branch carries secretory
fibers from the sphenopalatine ganglion to the
lacrimal gland.

28. 3-The posterior superior alveolar (PSA)
 (PSA) nerve descends from the main trunk of the
maxillary division in the pterygopalatine fossa just
before the maxillary division enters the infraorbital
canal.
 they reach the inferior temporal (posterior) surface
of the maxilla. When two trunks are present, one
remains external to the bone, continuing downward
on the posterior surface of the maxilla to provide
sensory innervation to the buccal gingiva in the
maxillary molar region and adjacent facial mucosal
surfaces.

29. 3-The posterior superior alveolar (PSA)
 the other branch enters into the maxilla (along with
a branch of the internal maxillary artery) through
the PSA canal to travel down the posterior or
posterolateral wall of the maxillary sinus, providing
sensory innervation to the mucous membrane of
the sinus.
 Continuing downward, this second branch of the
PSA nerve provides sensory innervation to the
alveoli, periodontal ligaments, and pulpal tissues of
the maxillary third, second, and first molars (with
the exception [in 28% of patients] of the
mesiobuccal root of the first molar).

30. 1. Maxillary Nerve.
2. posterior superior
alveolar branches.

31.  Within the infraorbital canal, the maxillary
division (V2) “infraorbital nerve” gives off two
branches of significance in dentistry:
I. The middle superior alveolar nerve.
II. The Anterior superior alveolar nerve.

32.  Branches to form a part of the superior dental
plexus, composed of the posterior, middle, and
anterior superior alveolar nerves.
 The MSA nerve provides sensory innervation to
the two maxillary premolars and, perhaps, to the
mesiobuccal root of the first molar and
periodontal tissues, buccal soft tissue, and bone
in the premolar region.
 Note:Traditionally it has been stated that the
MSA nerve is absent in 30% to 54% of
individuals.

33.  Branch is given off the infraorbital nerve (V2)
approximately 6 to 10 mm before the latter exits
from the infraorbital foramen.
 Descending within the anterior wall of the
maxillary sinus, it provides pulpal innervation to
the central and lateral incisors and the canine,
and sensory innervation to the periodontal
tissues, buccal bone, and mucous membranes of
these teeth.
 Note: In persons without an MSA nerve, the ASA
nerve frequently provides sensory innervation to
the premolars and occasionally to the
mesiobuccal root of the first molar.

34. 1. Branches of the
ASA nerve.
2. superior dental
plexus.
3.dental branches.
4.interdental and
interradicular
branches.

36.  The infraorbital nerve emerges through the
infraorbital foramen onto the face to divide into
its terminal branches:-
1. inferior palpebral nerve : provide sensory
supply to the skin of the lower eyelid.
2. External (lateral) nasal nerve: provide sensory
innervation to the skin on the lateral aspect of
the nose.
3. superior labial nerve : provide sensory
innervation to the skin and mucous membranes
of the upper lip.

37.  The mandibular division (V3) travels almost
directly downward to exit the skull, along
with the small sensory and large motor root,
through the foramen ovale.These two roots
then intermingle, forming one nerve trunk
that remains undivided for only 2 to 3 mm
before it splits into a small anterior and a
large posterior division.

38.  The mandibular division (V3)branches
1-Trunk.
a. nervus spinosus (meningeal branch of the
mandibular nerve). It reenters the cranium
through the foramen spinosum to supply the
dura mater and mastoid air cells.
b. medial pterygoid nerve.
- motor nerve to the medial pterygoid muscle.
- tensor veli palatini.
- tensor tympani.

40.  The mandibular division (V3)branches
2- Branches from the Anterior Division:-
A- buccal nerve (long buccal) or (buccinator nerve)
 sensory innervation to the mucous membrane
of the cheek and the buccal mucous
membrane of the mandibular molars
B- deep temporal nerves.
C- Massetric nerve.
D- lateral pterygoid nerves.
Motor
innervation to
the muscles of
mastication

42.  The mandibular division (V3)branches
3- Branches of the Posterior Division.
A- Auriculotemporal nerve:
 sensory, secretory, and vasomotor fibers to
the parotid gland ( the secretomotor fibers
are from the otic ganglion)

43. B- The lingual nerve :
 It passes downward medial to the lateral
pterygoid muscle and, as it descends, lies
between the ramus and the medial pterygoid
muscle in the pterygomandibular space.
 It runs anterior and medial to the inferior
alveolar nerve, whose path it parallels.

44. B- The lingual nerve :
 The lingual nerve is the sensory tract to the
anterior two thirds of the tongue. It provides
general sensation for this region. whereas the
chorda tympani (a branch of the facial nerve)
supplies fibers for gustation (taste).
 provides sensory innervation to the mucous
membranes of the floor of the mouth and the
gingiva on the lingual of the mandible

45. C-The inferior alveolar nerve :
 The largest branch of the mandibular division.
 It descends medial to the lateral pterygoid
muscle and lateroposterior to the lingual
nerve.
 enters the mandibular canal at the level of the
mandibular foramen between the
sphenomandibular ligament and the medial
surface of the mandibular ramus.

46. C-The inferior alveolar nerve :
 travel anteriorly in the mandibular canal as far
forward as the mental foramen, where the
nerve divides into its terminal branches:
1. the incisive nerve
2. the mental nerve.
 Note: Double inferior alveolar nerves and
mandibular canals were evident in 0.95% of
studied cases.
(Extremely rare)

47. C-The inferior alveolar nerve :
 The dental plexus serves the mandibular posterior teeth,
entering through their apices and providing pulpal
innervation.
 The incisive nerve remains within the mandibular canal
and forms a nerve plexus that innervates the pulpal
tissues of the mandibular first premolar, canine, and
incisors via the dental branches.
 The mental nerve exits the canal through the mental
foramen and divides into three branches that innervate
the skin of the chin and the skin and mucous membrane
of the lower lip.

49. D-The mylohyoid nerve
 Branches from the inferior alveolar nerve before entry of
the latter into the mandibular canal.
 The mylohyoid is a mixed nerve :-
1- being motor to the mylohyoid muscle and the anterior
belly of the digastric.
2- contain sensory fibers that supply the skin on the
inferior and anterior surfaces of the mental protuberance
 Note: May provide sensory innervation to the
mandibular incisors or the mandibular molars in some
persons, usually the mesial root of the mandibular first
molar.

51. References
1. Handbook of Local Anesthesia , 6th Edition 2013
by Stanley F. Malamed, DDS.
2. Local Anesthesia for Dental Professionals, 2nd
Edition by Kathy bassett